/* Test file for mpfr_const_log2.

Copyright 1999, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
Contributed by the Arenaire and Cacao projects, INRIA.

This file is part of the MPFR Library.

The MPFR Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version.

The MPFR Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the MPFR Library; see the file COPYING.LIB.  If not, write to
the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
MA 02110-1301, USA. */

#include <stdio.h>
#include <stdlib.h>

#include "mpfr-test.h"

/* tlog2 [prec] [rnd] [0 = no print] */

static void
check (mp_prec_t p0, mp_prec_t p1)
{
  mpfr_t x, y, z;
  mp_rnd_t rnd;
  int dif;

  mpfr_init (x);
  mpfr_init (y);
  mpfr_init2 (z, p1 + 10);
  mpfr_const_log2 (z, GMP_RNDN);
  mpfr_clear_cache (__gmpfr_cache_const_log2);

  for (; p0<=p1; p0++)
    {
      mpfr_set_prec (x, p0);
      mpfr_set_prec (y, p0);
        {
          rnd = (mp_rnd_t) RND_RAND ();
          mpfr_const_log2 (x, rnd);
          mpfr_set (y, z, rnd);
          if ((dif = mpfr_cmp (x, y))
              && mpfr_can_round (z, mpfr_get_prec(z), GMP_RNDN,
                                                 rnd, p0))
            {
              printf ("mpfr_const_log2 fails for prec=%u, rnd=%s Diff=%d\n",
                      (unsigned int) p0, mpfr_print_rnd_mode (rnd), dif);
              printf ("expected "), mpfr_dump (y);
              printf ("got      "), mpfr_dump (x);
              exit (1);
            }
        }
    }

  mpfr_clear (x);
  mpfr_clear (y);
  mpfr_clear (z);
}

static void
check_large (void)
{
  mpfr_t x, y;
  mpfr_init2 (x, 25000);
  mpfr_init2 (y, 26000);
  (mpfr_const_log2) (x, GMP_RNDN); /* First one ! */
  (mpfr_const_log2) (y, GMP_RNDN); /* Then the other - cache - */
  mpfr_prec_round (y, 25000, GMP_RNDN);
  if (mpfr_cmp (x, y))
    {
      printf ("const_log2: error for large prec\n");
      exit (1);
    }

  /* worst-case with 15 successive ones after last bit,
     to exercise can_round loop */
  mpfr_set_prec (x, 26249);
  mpfr_const_log2 (x, GMP_RNDZ);

  mpfr_clears (x, y, (mpfr_ptr) 0);
}

static void
check_cache ()
{
  mpfr_t x;
  int i;

  mpfr_init2 (x, 195);
  mpfr_free_cache ();
  i = mpfr_const_log2 (x, GMP_RNDN);
  if (i == 0)
    {
      printf("Error for log2. Invalid ternary value (1).\n");
      exit (1);
    }
  mpfr_set_prec (x, 194);
  i = mpfr_const_log2 (x, GMP_RNDN);
  if (i == 0)
    {
      printf("Error for log2. Invalid ternary value (2).\n");
      exit (1);
    }

  mpfr_free_cache ();
  mpfr_set_prec (x, 9);
  mpfr_const_log2 (x, GMP_RNDN);
  mpfr_set_prec (x, 8);
  mpfr_const_log2 (x, GMP_RNDN);
  if (mpfr_cmp_str (x, "0.10110001E0", 2, GMP_RNDN))
    {
      printf("Error for log2. Wrong rounding.\n");
      exit (1);
    }

  mpfr_clear (x);
}

int
main (int argc, char *argv[])
{
  mpfr_t x;
  int p;
  mp_rnd_t rnd;

  tests_start_mpfr ();

  p = (argc>1) ? atoi(argv[1]) : 53;
  rnd = (argc>2) ? (mp_rnd_t) atoi(argv[2]) : GMP_RNDZ;

  mpfr_init (x);

  check (2, 1000);

  /* check precision of 2 bits */
  mpfr_set_prec (x, 2);
  mpfr_const_log2 (x, GMP_RNDN);
  if (mpfr_cmp_ui_2exp(x, 3, -2)) /* 3*2^-2 */
    {
      printf ("mpfr_const_log2 failed for prec=2, rnd=GMP_RNDN\n"
              "expected 0.75, got ");
      mpfr_out_str(stdout, 10, 0, x, GMP_RNDN);
      putchar('\n');
      exit (1);
    }

  if (argc>=2)
    {
      mpfr_set_prec (x, p);
      mpfr_const_log2 (x, rnd);
      printf ("log(2)=");
      mpfr_out_str (stdout, 10, 0, x, rnd);
      puts ("");
    }

  mpfr_set_prec (x, 53);
  mpfr_const_log2 (x, GMP_RNDZ);
  if (mpfr_cmp_str1 (x, "6.9314718055994530941e-1") )
    {
      printf ("mpfr_const_log2 failed for prec=53\n");
      exit (1);
    }

  mpfr_set_prec (x, 32);
  mpfr_const_log2 (x, GMP_RNDN);
  if (mpfr_cmp_str1 (x, "0.69314718060195446"))
    {
      printf ("mpfr_const_log2 failed for prec=32\n");
      exit (1);
    }

  mpfr_clear(x);

  check_large();
  check_cache ();

  tests_end_mpfr ();
  return 0;
}
